• Journal of Korean Neurosurgical Society
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• v.62 no.4
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• pp.450-457
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• 2019

Objective : Anterior cervical discectomy and fusion (ACDF) is commonly used surgical procedure for cervical degenerative disease. Among the various intervertebral spacers, the use of allografts is increasing due to its advantages such as no harvest site complications and low rate of subsidence. Although subsidence is a rare complication, graft collapse is often observed in the follow-up period. Graft collapse is defined as a significant graft height loss without subsidence, which can lead to clinical deterioration due to foraminal re-stenosis or segmental kyphosis. However, studies about the collapse of allografts are very limited. In this study, we evaluated risk factors associated with graft collapse. Methods : We retrospectively reviewed 33 patients who underwent two level ACDF with anterior plating using allogenous bone graft from January 2013 to June 2017. Various factors related to cervical sagittal alignment were measured preoperatively (PRE), postoperatively (POST), and last follow-up. The collapse was defined as the ratio of decrement from POST disc height to follow-up disc height. We also defined significant collapses as disc heights that were decreased by 30% or more after surgery. The intraoperative distraction was defined as the ratio of increment from PRE disc height to POST disc height. Results : The subsidence rate was 4.5% and graft collapse rate was 28.8%. The pseudarthrosis rate was 16.7% and there was no association between pseudarthrosis and graft collapse. Among the collapse-related risk factors, pre-operative segmental angle (p=0.047) and intra-operative distraction (p=0.003) were significantly related to allograft collapse. The cut-off value of intraoperative distraction ${\geq}37.3%$ was significantly associated with collapse (p=0.009; odds ratio, 4.622; 95% confidence interval, 1.470-14.531). The average time of events were as follows: collapse, $5.8{\pm}5.7months$; subsidence, $0.99{\pm}0.50months$; and instrument failure, $9.13{\pm}0.50months$. Conclusion : We experienced a higher frequency rate of collapse than subsidence in ACDF using an allograft. Of the various preoperative factors, intra-operative distraction was the most predictable factor of the allograft collapse. This was especially true when the intraoperative distraction was more than 37%, in which case the occurrence of graft collapse increased 4.6 times. We also found that instrument failure occurs only after the allograft collapse.

• Journal of the Korea Institute of Building Construction
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• v.19 no.2
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• pp.185-192
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• 2019

Construction has been well known as the industry in which accidents occur more often than other industries. The efforts to eliminate the accidents at construction sites need to be continuously conducted because they tend to cause the social problems such as massive loss of life and property. According to the Korea Occupational Safety and Health Agency (KOSHA), 26,570 (29.3 percent) out of 90,656 workers in total industrial accidents have been occurred in the construction industry in 2016. Particularly, the falling victims are the largest number, which is about 8,699. This number is increasing due to the increase of the large scale, high-rise, and complex construction structures and the various construction methods. In reality, there is a lack of analysis on the risk factors of safety accidents and preventive measures. Therefore, in this study, we have selected risk factors by analyzing the accident cases at construction sites. Based on the results, we conducted a safety practitioner-focused survey and had an interview with safety managers. In analyzing the cases, we have categorized them into three groups such as upper, middle, and lower and compared their statistical results. This study are expected to provide safety management guidelines with workers and safety managers to prevent previously fall accidents at construction site.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.26 no.3
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• pp.167-182
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• 2021

This study was carried out to investigate temporal and spatial distribution of macrobenthic community and elucidate effects of environmental factors on change of community structure in an intertidal flat, Hakseong-ri, Boryeong, Korea. Field surveys were seasonally conducted to collect samples of sediment and macrobenthos using can core in triplicate at nine stations in 2016 and 2017. Our results showed that sediment had high mud content (above 60%) in most samples and mean content of loss on ignition was 2.3% in 2016. A total of 79 species was collected in the study site during the study period. Mean density and biomass were 611 ind./m² and 64.1 gWWt/m², respectively. Heteromastus filiformis was the dominant species (48.6%, 297 ind./m²) followed by Macrophthalmus japonicus (10.1%, 62 ind./m²) and Upogebia major (6.9%, 42 ind./m²). Three assembly groups resulted from cluster analysis were more distinguished by interaction between organisms and frequency of dominant species than by physical and chemical environment characteristics. In addition, macrobenthic community in the Hakseong intertidal flat showed seasonal changes based on non metric multidimensional scaling using species abundance.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.6
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• pp.34-41
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• 2020

In recent years, magnitude and frequency of earthquakes have increased in Korea. Damage to a bridge, which is one of the main infrastructures, can directly lead to considerable loss of human lives. Therefore, engineers need to evaluate the seismic fragility of the structure and prepare for the possible seismic damage. In particular, the number of aging bridges over 30 years of service increases, and thus the seismic analysis and fragility requires accounting for the aging and retrofit effects on the bridge. In this study, the nonlinear static and dynamic analyses were performed to evaluate the effects of the aging and FRP retrofit on a PSC bridge. The aging and FRP retrofit were applied to piers that dominate the response of the bridge during earthquakes. The maximum displacement of the bridge increased due to the aging of the pier but decreased when FRP retrofit applied to the aged pier. In addition, seismic fragility analysis was performed to evaluate the seismic behavior of the bridge combined with the seismic performance of the pier. Compared with the aged bridge, the FRP retrofit bridge showed a decrease in the seismic fragility in all levels of damage. The reduction of the seismic fragility in the FRP bridge was prominent as the value of PGA and level of damage increased.

• Journal of Korean Neurosurgical Society
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• v.65 no.5
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• pp.665-679
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• 2022

Objective : Patients with mild ischemic stroke experience various sequela and residual symptoms, such as anxious behavior and deficits in movement. Few approaches have been proved to be effective and safe therapeutic approaches for patients with mild ischemic stroke by acute stroke. Sildenafil (SIL), a phosphodiesterase-5 inhibitor (PDE5i), is a known remedy for neurodegenerative disorders and vascular dementia through its angiogenesis and neurogenesis effects. In this study, we investigated the efficacy of PDE5i in the emotional and behavioral abnormalities in rats with mild ischemic stroke. Methods : We divided the rats into four groups as follows (n=20, respectively) : group 1, naïve; group 2, middle cerebral artery occlusion (MCAo30); group 3, MCAo30+SIL-pre; and group 4, MCAo30+SIL-post. In the case of drug administration groups, single dose of PDE5i (sildenafil citrate, 20 mg/kg) was given at 30-minute before and after reperfusion of MCAo in rats. After surgery, we investigated and confirmed the therapeutic effect of sildenafil on histology, immunofluorescence, behavioral assays and neural oscillations. Results : Sildenafil alleviated a neuronal loss and reduced the infarction volume. And results of behavior task and immunofluorescence shown possibility that anti-inflammation process and improve motor deficits sildenafil treatment after mild ischemic stroke. Furthermore, sildenafil treatment attenuated the alteration of theta-frequency rhythm in the CA1 region of the hippocampus, a known neural oscillatory marker for anxiety disorder in rodents, induced by mild ischemic stroke. Conclusion : PDE5i as effective therapeutic agents for anxiety and movement disorders and provide robust preclinical evidence to support the development and use of PDE5i for the treatment of mild ischemic stroke residual disorders.

• Journal of Space Technology and Applications
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• v.1 no.1
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• pp.33-40
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• 2021

Based on the requirements of a total weight of 42 kg or less, the NEXTSat-2 SAR (synthetic aperture radar) system was developed. As the NEXTSat-2 is a small-sized satellite, the SAR system was designed to account for about 40% of the dry mass of the payload relative to the total mass. Among the major components of the SAR system - which are an antenna, an RF transceiver, a baseband signal processor, and a power unit - a part with a particularly large dry mass is the antenna, the core of the SAR system. Whereas various selections are possible in consideration of gain and efficiency when designing the antenna, the micro-strip patch array antenna was adopted by reflecting the dry mass, power, and resolution required by the NEXTSat-2 project. In order to meet the mission requirement of the NEXTSat-2, the antenna was developed with a frequency of 9.65 GHz, a gain of 42.7 dBi, and a return loss of -15 dB. The performance of the antenna was verified by conducting a field test onboard the vehicle.

• Geophysics and Geophysical Exploration
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• v.24 no.4
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• pp.180-193
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• 2021

The complex resistivity method is an exploration technique that can obtain various characteristic information of underground media by measuring resistivity and phase in the frequency domain, and its utilization has recently increased. In this paper, a three-dimensional inversion algorithm for the CR data was developed to increase the utilization of this method. The Poisson equation, which can be applied when the electromagnetic coupling effect is ignored, was applied to the modeling, and the inversion algorithm was developed by modifying the existing algorithm by adopting comlex variables. In order to increase the stability of the inversion, a technique was introduced to automatically adjust the Lagrangian multiplier according to the ratio of the error vector and the model update vector. Furthermore, to compensate for the loss of data due to noisy phase data, a two-step inversion method that conducts inversion iterations using only resistivity data in the beginning and both of resistivity and phase data in the second half was developed. As a result of the experiment for the synthetic data, stable inversion results were obtained, and the validity to real data was also confirmed by applying the developed 3D inversion algorithm to the analysis of field data acquired near a hydrothermal mine.

• Korean Journal of Biological Psychiatry
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• v.29 no.1
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• pp.22-31
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• 2022

Objectives Recently, weight loss has emerged as a national concern in South Korea, and this has resulted in an increase in the frequency of use of central nervous system (CNS)-stimulating appetite suppressants. This study aimed to collect cases of psychotic disorders and bipolar disorders triggered by phentermine and phendimetrazine and explore the clinical features and courses. Methods In this retrospective study, we analyzed the electronic medical records of patients and selected eight patients who developed psychotic symptoms and manic symptoms for the first time after taking phentermine and phendimetrazine. All cases were reviewed, and their clinical features and course were summarized. Results All eight patients developed psychotic symptoms, and one had accompanying manic symptoms. The final diagnosis was appetite-suppressant-induced psychotic disorder in four patients, schizophrenia in three, and appetite-suppressant-induced bipolar disorder in one. In addition, three patients were diagnosed as having substance-use disorder. The key psychotic symptoms of these patients were hallucinations and paranoia. Conclusions These case findings suggest that phentermine and phendimetrazine can cause psychotic disorder, bipolar disorder, or substance use disorder and that medical professionals and the public should practice caution when prescribing and using these drugs.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.35 no.3
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• pp.25-35
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• 2022

Objectives : This study is designed to analyze outpatients who received medical treatments in ophthalmology, otolaryngology & dermatology clinic in Cheonan for 3 years. Based on the results, we intend to identify the trends of outpatients and provide the base data that can be used for future researches on patient characteristics, and Korean medicine treatments on field, statistical surveys, policy setting related to medical services. Methods : We retrospectively analyzed outpatients according to gender, year, age, season, main diagnosis, number of visits. The statistical analysis performed using IBM SPSS 25.0 for Windows. Results : The results of analyzing the electronic medical records of 1,260 patients are as follows. 1. Patients increased in 2019 compared to 2018, but decreased due to the influence of COVID-19 in 2020, and women visited more than men. The most visited age group was 40s and 50s, and summer was the highest in season. 2. By analyzing the number of visits per patient, men visited more than women, under the age of 20 was highest in age group and spring was highest in season. 3. Every year, sudden hearing loss, a frequent disease in otology, increased, and rhinitis, a frequent disease in ophthalmology, decreased. And the proportion of patients in dermatology was about 30% of the total 100 diseases. Conclusions : In order to increase the supply and use of Korean medicine in the Cheonan area in the future, it is essential to provide support at the association level and systematic supplement at the government level in consideration of the characteristics of the patient group and the trend of frequency diseases.

• Korean Journal of Veterinary Service
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• v.45 no.4
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• pp.325-330
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• 2022

Distichiasis is one of the diseases commonly encountered in companion animals, and these abnormal eyelashes cause corneal ulcers, continuous eye irritation, eye pain, glare, epiphora, foreign body sensation and can cause corneal opacity and vision loss in severe cases. In this study, an eyelash epilation needle for animals was developed and applied to a real case, and the results were observed. In a case of corneal ulcer caused by distichiasis of a 2-year-old Shih Tzu, a high-frequency surgical instrument for animals was converted into an electric epilation needle to attempt a procedure to destroy the eyelash hair follicles on the upper eyelid. A epilation needle was developed to have a diameter of 0.1 mm and a length of 4 mm at the end of the handle of DOCTANZ 400, an electrosurgical instrument for animals only. In the procedure, 2~3 mm of an epilation needle was inserted into the hair follicle, and 1 watt of electric power was applied to the hair follicle for about 5 sec. to carry out electrolysis until white bubbles were generated around the meibomian glands thereby destroying the hair follicle. As a result, no eyelashes grew any longer in the treated area indicating that the treatment was successful. It is hoped that the method developed in this study will be applied so that it will be widely used as a treatment method for distichiasis in companion animals that can be frequently seen hereafter.